• Purity

  >97%, by SDS-PAGE under reducing conditions and visualized by silver stain

• Endotoxin Level

  <0.10 EU per 1 μg of the protein by the LAL method.  

• Activity

  Measured in a cell proliferation assay using MO7e human megakaryocytic leukemic cells. Avanzi, G.     et al. (1988) Br. J. Haematol.     69:359. The ED    ₅₀ for this effect is 0.4‑2.4 ng/mL.

• Source

  Mouse myeloma cell line, NS0-derived Ser22-Thr356

• Accession #

• N-terminal Sequence    
  Analysis

  Ser22

• Predicted Molecular Mass

  35 kDa

• SDS-PAGE

  80-90 kDa, reducing conditions

Carrier Free

What does CF mean?

CF stands for Carrier Free (CF). We typically add Bovine Serum Albumin (BSA) as a carrier protein to our recombinant proteins. Adding a carrier protein enhances protein stability, increases shelf-life, and allows the recombinant protein to be stored at a more dilute concentration. The carrier free version does not contain BSA.

What formulation is right for me?

In general, we advise purchasing the recombinant protein with BSA for use in cell or tissue culture, or as an ELISA standard. In contrast, the carrier free protein is recommended for applications, in which the presence of BSA could interfere.

Data Images

Background: Thrombopoietin/Tpo

Thrombopoietin (Tpo), is a key regulator of megakaryocytopoiesis and thrombopoiesis. It is principally produced in the liver and is bound and internalized by the receptor Tpo R/c-mpl. Defects in the Tpo-Tpo R signaling pathway are associated with a variety of platelet disorders (1-3). The 356 amino acid (aa) mouse Tpo precursor is cleaved to yield the 335 aa mature protein. Mature mouse Tpo shares 71% and 81% aa sequence homology with human and rat Tpo, respectively. It is an 80-85 kDa protein that consists of an N-terminal domain with homology to Erythropoietin (Epo) and a C-terminal domain that contains multiple N-linked and O-linked glycosylation sites (4, 5). Tissue specific alternate splicing of mouse Tpo generates multiple isoforms with internal deletions, insertions, and/or C-terminal substitutions (6). Tpo promotes the differentiation, proliferation, and maturation of MK and their progenitors (4, 5, 7). Several other cytokines can promote these functions as well but only in cooperation with Tpo (8, 9). Notably, IL-3 independently induces MK development, although its effects are restricted to early in the MK lineage (8, 9). Tpo additionally promotes platelet production, aggregation, ECM adhesion, and activation (10-13). It is cleaved by platelet-derived thrombin following Arg191 within the C‑terminal domain and subsequently at other sites upon extended digestion (14). Full length Tpo and shorter forms circulate in the plasma (4, 5). The C‑terminal domain is not required for binding to Tpo R or inducing MK growth and differentiation (5). Aside from its hematopoietic effects, Tpo is expressed in the brain where it promotes the apoptosis of hypoxia-sensitized neurons and inhibits neuronal differentiation by blocking NGF-induced signaling (15, 16).

• References:

1. Deutsch, V.R. and A. Tomer (2006)J. Haematol.         134:453.

2. Kaushansky, K. (2005) J. Clin. Invest.         115:3339.

3. Li, J. et al. (1999)J. Haematol.         106:345.

4. Bartley, T.D.         et al. (1994) Cell         77:1117.

5. de Sauvage, F.J.         et al. (1994) Nature         369:533.

6. Marcucci, R. and M. Romano  (2008) Biochim. Biophys. Acta         1782:427.

7. Kaushansky, K.         et al. (1994) Nature         369:568.

8. Kaushansky, K.         et al. (1995) Proc. Natl. Acad. Sci.         92:3234.

9. Broudy, V.C.         et al. (1995) Blood         85:1719.

10. Lok, S.I.         et al. (1994) Nature         369:565.

11. Chen, J.         et al. (1995) Blood         86:4054.

12. Oda, A.         et al. (1996) Blood         87:4664.

13. Van Os, E.         et al. (2003) Br. J. Haematol.         121:482.

14. Kato, T.         et al. (1997) Proc. Natl. Acad. Sci.         94:4669.

15. Ehrenreich, H.         et al. (2005) Proc. Natl. Acad. Sci.         102:862.

16. Samoylenko, A. et al. (2008) Cell. Signal. 20:154.

• Entrez Gene IDs:

  7066 (Human); 21832 (Mouse); 81811 (Rat)

• Alternate Names:

  Megakaryocyte colony-stimulating factor; Megakaryocyte growth and development factor; megakaryocyte stimulating factor; MGDF; MGDFC-mpl ligand; MK-CSF; ML; MPL ligand; MPLLGMGC163194; Myeloproliferative leukemia virus oncogene ligand; THPO; thrombopoietin nirs variant 1; Thrombopoietin; Tpo; TPOMKCSF